Many different orthopedic casting materials have been developed for use in the immobilization of broken or otherwise injured body limbs. Some of the first casting materials developed for this purpose involved the use of plaster of Paris bandages consisting of a cotton gauze mesh fabric with plaster incorporated into the openings and onto the surface of the mesh fabric. Plaster of Paris casts, however, have a number of attendant disadvantages, including a low strength-to-weight ratio, resulting in a finished cast which is very heavy and bulky. In addition, plaster of Paris casts develop their strength over a relatively long period of time, thus making it necessary to avoid weight bearing situations for up to 24 to 48 hours. Furthermore, plaster of Paris casts typically disintegrate in water, thus making it necessary to avoid bathing, showering, or other activities involving contact with water.
A significant advancement in the art was achieved when synthetic polyisocyanate prepolymers were found to be useful in orthopedic casting materials. Typical commercially available synthetic casting materials comprise a knit fiberglass fabric backing impregnated with a polyisocyanate prepolymer resin. These casting materials can provide significant advancement over the plaster of Paris casts, including a higher strength-to-weight ratio. Unfortunately, however, knitted fiberglass backings of conventional casting articles may become quite rough when cured and often produce casts with sharp edges. The sharp edges can cause skin abrasions and/or snag clothing. As a result, the health care worker has had to employ padding materials at the edges to attempt to avoid contact of the casting article with the skin.
A modified synthetic casting material was developed for use in non-weight bearing applications. These softer, more flexible casting materials (e.g., "SOFTCAST" from 3M) are typically used for functional immobilizations that can tolerate some movement (e.g., non-serious, minor broken bones; or more typically strains, sprains, and ligament damage). Recently, these softer materials have been used together with the conventional harder, stiffer casting tapes for functional immobilization. In a typical use, one or more strips of the harder, stiffer casting tape are laid down on the surface of the cast and covered with additional layers of the softer more flexible material. This application technique is somewhat cumbersome, and requires the health care worker to handle two different casting tapes. Furthermore, generally only a portion of a roll of the harder, stiffer material is needed for the reinforcement. The remainder is generally wasted as it will cure within a short time after having been taken from its pouch.